d-andl-isomers of serine and alanine equally effective as releasers of gastrin

Zusammenfassung l-undl-Isomere von Alanin und Serin sind beide wirksam, von der Antrumschleimhaut aus den Gastrinmechanismus zu aktivieren.

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This work was supported by Veterans Administration research funds and by grants from the US Public Health Service.     

HIV preferentially infects HIV-specific CD4+ T cells

HIV infection is associated with the progressive loss of CD4(+) T cells through their destruction or decreased production. A central, yet unresolved issue of HIV disease is the mechanism for this loss, and in particular whether HIV-specific CD4(+) T cells are preferentially affected. Here we show that HIV-specific memory CD4(+) T cells in infected individuals contain more HIV viral DNA than other memory CD4(+) T cells, at all stages of HIV disease. Additionally, following viral rebound during interruption of antiretroviral therapy, the frequency of HIV viral DNA in the HIV-specific pool of memory CD4(+) T cells increases to a greater extent than in memory CD4(+) T cells of other specificities. These findings show that HIV-specific CD4(+) T cells are preferentially infected by HIV in vivo. This provides a potential mechanism to explain the loss of HIV-specific CD4(+) T-cell responses, and consequently the loss of immunological control of HIV replication. Furthermore, the phenomenon of HIV specifically infecting the very cells that respond to it adds a cautionary note to the practice of structured therapy interruption.     

Action of fully co-ordinated 1,10-phenanthroline transition metal chelates on the guinea-pig isolated atrium

Zusammenfassung Nachweis, dass vollkoordinierte zweiwertige Kupfer- und Nickelchelate des 3,4,7,8-Tetramethyl-1,10-phenanthrolins Muskelkraft, wie auch Kontraktionsgeschwindigkeit des isolierten Meerschweinchen Atriums, sowie H³-Noradrenalin- und Metabolitenausfluss vermehren. Die durch Chelate veranlasste Senkung des Noradrenalins konnte durch Fluoreszenz-Histochemie bestätigt werden.

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This work was commenced in the Department of Pharmacology, University of Melbourne and was presented in part by H. G. in November 1972 in partial fulfilment for the degree of B. Sc. (Hons) in the University of Melbourne.     

Isolation of canine gastrin

Zusammenfassung Die Isolierung von zwei Gastrinen aus der Magenschleimhaut von Hunden wird beschrieben.     

A pigment-binding protein essential for regulation of photosynthetic light harvesting

Photosynthetic light harvesting in plants is regulated in response to changes in incident light intensity. Absorption of light that exceeds a plant's capacity for fixation of CO2 results in thermal dissipation of excitation energy in the pigment antenna of photosystem II by a poorly understood mechanism. This regulatory process, termed nonphotochemical quenching, maintains the balance between dissipation and utilization of light energy to minimize generation of oxidizing molecules, thereby protecting the plant against photo-oxidative damage. To identify specific proteins that are involved in nonphotochemical quenching, we have isolated mutants of Arabidopsis thaliana that cannot dissipate excess absorbed light energy. Here we show that the gene encoding PsbS, an intrinsic chlorophyll-binding protein of photosystem II, is necessary for nonphotochemical quenching but not for efficient light harvesting and photosynthesis. These results indicate that PsbS may be the site for nonphotochemical quenching, a finding that has implications for the functional evolution of pigment-binding proteins.     

Host immune rejection of TA3 ascites carcinoma cells following administration of a water soluble carbodiimide.

Regression of TA3 ascites carcinoma tumors occurred following i.p. injection of 1-ethyl-3-(3'-dimethylaminopropyl)carbodiimide-HC1. An immunological mechanism of drug action was indicated by the fact that no significant antitumor activity was demonstrable in mice that had previously received an immunosuppressive 700 rad dose of 60Co radiation.